4.1 What is the level of exposure when using toothpastes and mouth-rinses containing hydrogen peroxide?

Studies have shown that hydrogen peroxide present in toothpaste is rapidly broken down by the saliva and that other toothpaste ingredients, such as fluoride or sodium bicarbonate do not interfere with this process. One study found that 70% of the hydrogen peroxide was broken downduring the first minute of brushing.

Some of the toothpaste and mouth rinse used is swallowed:

It is estimated that on average, the total amount of toothpaste a person ingests per day is 0.48 g, Assuming that the toothpaste used contains 0.1% hydrogen peroxide, the amount of hydrogen peroxide swallowed would be 0.48 mg.

The estimated average amount of mouth rinses ingested daily is 3 g. If the mouth rinse contains 0.1% hydrogen peroxide, the resulting amount of hydrogen peroxide ingested per day will be 3 mg.

Several clinical trials were conducted with toothpastes and mouth rinses containing hydrogen peroxide over several weeks and months. All these studies seem to have been conducted or sponsored by manufactures of oral hygene products.

using toothpastes containing up to 1.5% of hydrogen peroxide twice a day for up to six months did not lead to adverse health effects related to hydrogen peroxide.

using mouth rinses that contain up to 1.5% hydrogen peroxide once or twice daily for up to 2 years had no adverse effects on the inside of the mouth, gums or tongue. However, one study reported discoloration of the inner lining of the mouth and the tongue when used 4 times daily for 5 weeks.

rinses containing 3% hydrogen peroxide used 3 to 5 times per day can cause irritation in people with a previous mouth injury; and

rinsing and brushing 2 to 3 times daily with products containing more than 6% hydrogen peroxide did affect the tongue and gums in some healthy people.

During the 1990s millions of units of toothpastes containing 0.75% hydrogen peroxide were sold in the USA. This market experience indicates that toothpastes containing 0.75% hydrogen peroxide are well tolerated, with one adverse effect reported for 100 000 sold products (between 1991 and 1994). This rate of reporting and the nature of the reports were similar to that for other toothpastes marketed in the USA. More...

4.2 What is the level of exposure during a tooth whitening treatment?

When people undergo tooth whitening treatment, the amount of hydrogen peroxide that is released into the saliva depends mostly on the bleaching system used and depends only partially on the amount of saliva produced by the individual.

During the first 30 to 60 minutes of tooth whitening treatment, the concentration of hydrogen peroxide at the gums and in the saliva falls very quickly, because hydrogen peroxide is rapidly broken down.

A tooth whitening strip with 6% hydrogen peroxide contains about 12 mg of hydrogen peroxide. A study estimated that people using 4 such tooth whitening strips per day, swallow about 4.8 to 11.4 mg hydrogen peroxide per day. However, since the flow of saliva – which affects the calculations – is likely to be greater when the strips are applied, actual exposure may be greater. Swallowing an entire strip – which can occasionally happen – results in an exposure of about 12 mg hydrogen peroxide.

The estimated exposure to hydrogen peroxide through tooth whitening mouthguards containing 10% carbamide peroxide is about 1.68 to 4.2 mg per day considering that a person swallows 10 to 25% of the whithening gel in the mouthguard during application. The techniques used to make custom-fitted mouthguards and the tooth whiteners themselves have improved recently. Hence, modern treatments use a smaller amount of whitener than older methods.